A user device may include both hosts such as a personal computer, a digital camera, a camcorder, a cellular phone, an MP3 player, a PMP, a PDA, and the like and storage devices such as a memory card, an USB memory, a Solid State Drive (SSD), a Hard Disk Drive (HDD), and the like. For the user device, a storage device may be included within a host. The storage device may include volatile memories such as a DRAM, a SRAM, and the like and nonvolatile memories such as an EEPROM, a FRAM, a PRAM, an MRAM, a flash memory, and the like.
In case that any file of a host is deleted, a file system may manage the file to be a deleted file. That a file is deleted may mean that metadata of the deleted file as file system management data is changed. Although a file is deleted at a host level, that is, although metadata of a deleted file is changed by a file system, a storage device may not judge whether it is a deleted file.
For this reason, a merge operation or a garbage collection operation may be performed on invalid files within the storage device. This operation may make the performance of the storage device lower. Further, since invalid files are stored like valid data, a valid storage space of the storage device may be reduced.